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Lighting up homes and streets, one 2-liter bottle at a time

DIY street lights designed by the Liter of Light program are on display outside the U.N.'s Habitat III conference on cities. (Christopher Swope)

QUITO, Ecuador — Lighting up streets and homes, and all the health and safety benefits that come from it, doesn’t have to be expensive.

That’s the lesson of a project called LIter of Light, which is on display here this week in a park across the street from where the U. N.’s Habitat III summit on cities is taking place. And it has the potential to change the lives of more than 1 billion people who live in areas off the electricity grid.

The lamps are made out of 2-liter plastic soda bottles. The simplest ones can provide light with a mixture of filtered water and 10 ml of bleach — the bleach keeps algae from growing. When installed in a tin rooftop and glued into place so that half of the bottle is above the roof and half below, the water refracts sunlight and emits it into the home with the strength of a 3-watt light bulb. The water-bleach solution only needs changing once every five years.

These DIY lights are now lighting up more than half a million homes in 40 countries. They allow residents to get rid of kerosene lamps that give off unhealthy fumes. Illac Diaz, a social entrepreneur and chairman of the My Shelter Foundation, first chanced upon the idea in 2002 during his studies at MIT. “Open-source, locally made and affordable,” Diaz says. “These are the things that will make energy accessible to people who live in remote areas and have no access to electricity.”

The Liter of Light project holds workshops in villages to teach the men and women in the community how to build their own solar light bulb using locally sourced materials. The empty soda bottles often end up in landfills.

More advanced iterations of the lights use small solar panels to power LEDs inside the bottle. In El Ejido Park, these lamps were set up as street lights, hitched to tall stands made out of PVC pipes. At night, they gave off brighter light than the more conventional street lights in the park.

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(HabitatIII Secretariat)

The solar-panel installations add an entrepreneurship component to the solution. Women can charge a small fee for mobile-phone charging. Those who know how to install and repair the panels also earn an extra income.

The simple technology aims to provide a bottom-up approach to building clean energy solutions. In the Philippines, one enterprising man who attended a workshop has installed about 11,000 solar light bulbs in a province south of Manila known as Laguna, as well as in areas hit by typhoons.

The grassroots production of these micro-solar devices breaks traditional market models where solar solutions are often imported, patented and expensive. Diaz says producing these systems locally can save 60 percent of the cost. “Grassroots action is only effective when the households and the community own the solution themselves,” says Diaz. “Clean energy products will achieve scale using open-source and local materials — sustaining that requires they are built and repaired locally as well.”

After the Habitat III meeting, Diaz is holding workshops in the nearby Galapagos Islands, and will perform lighting installations in homes in the port city of Manta, which was hit recently by an earthquake. Future workshops and installations will be held in other parts of South America, Nepal and India.